Accessory hoists and dump bodies have been devised for use on pickup trucks to facilitate the loading and unloading of materials onto and from the truck bed. For example, U.S. Pat. No. 3,377,104 to T. F. Sherman is directed to a combination hoist and dump body for direct attachment to the bed of a pickup truck. The dump body itself is of rigid construction and pivotally attached at its rearward end to the rear end of the truck bed; and in turn the winch or hoist is affixed at the center of the front end of the body for the purpose of lifting the dump body about its pivotal axis in dumping the contents of the body off of the rear of the truck.
U.S. Pat. No. 1,453,663 to W. B. Engler discloses the use of a hoist and dump body in very much the same relationship as Sherman but wherein the hoist has a swinging mast and specifically wherein the mast is free to swing forwardly and rearwardly but not in a lateral direction.
U.S. Pat. No. 1,897,383 to G. W. Burgoyne is directed to the use of a pivotal boom member which can swing about a vertical axis and which is mounted at the front end of a vehicle opposite to the truck bed. Other representative patents are U.S. Pat. Nos. 1,506,136 to E. H. Remde; 2,033,209 to C. N. Teetor; 3,237,989 to L. R. Fulton; 3,411,825 to L. R. Fulton; 3,826,534 to G. G. Ruff; and 4,629,390 to D. D. Burke.
Although the broad combination of accessory hoist and dump box assembly is well known, no one to my knowledge has devised a secure but releasable means of attachment of a swivel hoist mechanism to the corner of a truck bed and in such a way as to enable its effective utilization in combination with a dump body or independently of the dump body in loading or unloading materials onto and from the truck bed. Furthermore, it is desirable to provide for an accessory dump body which can be effectively placed on the truck bed without direct attachment but nevertheless be pivotal about one end when used in combination with the hoist mechanism in dumping operations.